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Scattering center modeling for low-detectable targets

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Journal of Systems Engineering and Electronics 2022年第3期33卷 511-521页

作者： CHEN Yanxi GUO Kunyi XIAO Guangliang sheng xinqing Institute of Radio Frequency Technology and Software School of Integrated Circuits and ElectronicsBeijing Institute of TechnologyBeijing 100081China

The scattering centers(SCs)of low-detectable targets(LDTs)have a low scattering intensity.It is difficult to build the SC model of an LDT using the existing methods because these methods mainly concern dominant SCs with strong scattering contributions.This paper presents an SC modeling approach to acquire the weak SCs of LDTs.We employ the induced currents at the LDT to search SCs,and the joint time-frequency transform together with the Hough transform to separate the scattering contributions of different SCs.Particle swarm optimization(PSO)is applied to improve the estimation results of SCs.The accuracy of the SC model built by this approach is verified by a full-wave numerical method.The validation results show that the SC model of the LDT can precisely simulate the signatures of high-resolution images,such as high-resolution range profile and inverse synthetic aperture radar(ISAR)images.

关键词： low-detectable target(LDT) stealth target scattering center(SC)model time-frequency representation full-wave method

基于多区域面积分方程的电大非均匀等离子体电磁特性高效计算方法

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电波科学学报 2024年第1期39卷 26-38页

作者：张慧雯陈宇浩黄晓伟盛新庆北京理工大学集成电路与电子学院射频技术与软件研究所

针对临近空间等离子体包覆目标的电磁特性快速准确评估这一迫切需求，本文运用基于多区域面积分方程(multi-region surface integral equation, MR-SIE)的全波数值计算方法，展现电大尺度、非均匀、高负介电常数等离子体的电磁散射与辐... 详细信息

针对临近空间等离子体包覆目标的电磁特性快速准确评估这一迫切需求，本文运用基于多区域面积分方程(multi-region surface integral equation, MR-SIE)的全波数值计算方法，展现电大尺度、非均匀、高负介电常数等离子体的电磁散射与辐射问题的仿真能力。首先，推导了非均匀等离子体的MR-SIE，使用间断伽辽金(discontinuous Galerkin, DG)方法提高对多区域复杂等离子体目标的建模与计算效率，研究了不同方程的数值性能；随后针对电子密度较大的高负介电常数区等离子体，运用一种简洁高效的截断策略，进一步提升了多层快速多极子算法的鲁棒性，避免了SIE计算高损耗介质内问题面临的数值不稳定性。数值实验表明，该方法在计算多种分割方式的多区域等离子体鞘套模型时具有良好的精度和效率，可用于大尺度复杂等离子体目标电磁辐射与散射特性的快速精确评估。

关键词：多区域目标面积分方程(MR-SIE) 等离子体鞘套负介电常数多层快速多极子算法(MLFMA) 间断伽辽金(DG)

General and efficient parallel approach of finite element-boundary integral-multilevel fast multipole algorithm

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Journal of Systems Engineering and Electronics 2008年第2期19卷 207-212页

作者： Pan Xiaomin sheng xinqing Center for Electromagnetics Simulation School of Information Science and Technology Beijing Inst. of Technology Beijing 100081 P. R. China

A general and efficient parallel approach is proposed for the first time to parallelize the hybrid finiteelement-boundary-integral-multi-level fast multipole algorithm （FE-BI-MLFMA）. Among many algorithms of FE-BI-MLFMA, the decomposition algorithm （DA） is chosen as a basis for the parallelization of FE-BI-MLFMA because of its distinct numerical characteristics suitable for parallelization. On the basis of the DA, the parallelization of FE-BI-MLFMA is carried out by employing the parallelized multi-frontal method for the matrix from the finiteelement method and the parallelized MLFMA for the matrix from the boundary integral method respectively. The programming and numerical experiments of the proposed parallel approach are carried out in the high perfor- mance computing platform CEMS-Liuhui. Numerical experiments demonstrate that FE-BI-MLFMA is efficiently parallelized and its computational capacity is greatly improved without losing accuracy, efficiency, and generality.

关键词： finite element-boundary integral-multilevel fast multipole algorithm parallelization.

Simulation research on scattering characteristics by complex targets

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Journal of Systems Engineering and Electronics 2007年第4期18卷 685-691页

作者： Guo Kunyi sheng xinqing Center for Electromagnetic Simulation School of Information Science and Technology Beijing Inst. of Technology Beijing 100081 P. R. China

A simulation approach based on a full-wave numerical method is presented to study electromagnetic characteristics by complex targets. How to validate simulation results is considered thoroughly under no analytical and measured data, where a double-check criterion is designed for our simulation approach. As an example, the scattering of F-117A is studied by using our simulation approach under all polarizations, different frequency bands, incident and scattering directions, etc., some of which, such as cross-polarization, bistatic RCS, have not been considered in the previous literature.

关键词： electromagnetic characteristics simulation complex targets hybrid FE-BI-MLFMA.

THE ANGLE ERROR ESTIMATE METHOD IN THE WIDE SWATH SAR BASING ON MULTI-RECEIVER

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Journal of Electronics(China) 2006年第3期23卷 374-378页

作者： Wang Xiaoqing Zhu Minhui sheng xinqing National Key Lab of Microwave Imaging Technology Institute of Electronics Chinese Academy of Science Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100039 China

The wide-swath method based on multi-receiver is a novel and highly accurate wide-swath method, which requires a very precise view angle. The estimated angle has error because of the atmosphere refraction, angle error of view and target height. A method is proposed in this paper to estimate the angle error from the return signal. The method makes use of the relationship between the view angle error and the signal correlation of the subswaths to estimate the angle error. The precision of this method is analyzed by the law of great number and it turns out to be in direct proportion to the root square number of averaging. The simulation result is given and the angle precision is 0.025°.

关键词：人造孔径雷达 SAR 多接受器误差估计

Novel high-performance element in the electromagnetic finite-element method——node-edge element

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Journal of Systems Engineering and Electronics 2008年第5期19卷 878-881页

作者： sheng xinqing Peng Zhen Center for Electromagnetic Simulation School of Information Science and Technology Beijing Inst. of Technology Beijing 100081 P. R. China

It is known in the computational electromagnetics （CEM） that the node element has a relative wellconditioned matrix, but suffers from the spurious solution problem; whereas the edge element has no spurious solutions, but usually produces an ill-conditioned matrix. Particularly, when the mesh is over dense, the iterative solution of the matrix equation from edge element converges very slowly. Based on the node element and edge element, a node-edge element is presented, which has no spurious solutions and better-conditioned matrix. Numerical experiments demonstrate that the proposed node-edge element is more efficient than now-widely used edge element.

关键词： node-edge element node element edge element matrix condition number.

Accurate scattering centers modeling for complex conducting targets based on induced currents

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Science China(Information Sciences) 2021年第2期64卷 268-270页

作者： Guangliang XIAO Kunyi GUO Biyi WU xinqing sheng Institute of Applied Electromagnetic School of Information and ElectronicsBeijing Institute of Technology

Dear editor,According to the electromagnetic theory, each scattering center(SC) is equivalent to a mathematical discontinuity in Stratton-Chu integrals [1]. From the view of geometrical structure, the positions of SCs correspond to the discontinuities of surface and specular points. Therefore, the signatures of SCs in radar images can represent the actual geometric characteristics. Three-dimension SC model has been successfully applied for the radar target reconstruction and automatic target recognition(ATR) [2].

关键词： scattering center model induced currents complex target time-frequency representation (TFR) parameter estimation

Estimation of vector miss distance for complex objects based on scattering center model

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Science China(Information Sciences) 2021年第4期64卷 235-237页

作者： Jie WU Kunyi GUO Biyi WU xinqing sheng Institute of Applied Electromagnetic School of Information and ElectronicsBeijing Institute of Technology

Dear editor,This study presents a method to estimate vector miss distance (VMD) for complex objects based on scattering center (SC) models. In the method, the dependence of the SCs on the aspect angle of the light of sight (LOS) is applied in VMD estimation. This method requires only the radar echoes in a short time frame when the flying object approaches to the closet point of approach (CPA).

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Efficient Computation of Scattering from Targets with Negative Impedance Surface

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Journal of Beijing Institute of Technology 2017年第1期26卷 90-94页

作者： Jingwei Hao Hongwei Gao xinqing sheng School of Information and Electronics Beijing Institute of Technology Beijing 100081 China

Current surface integral equations used for computing scattering from targets with negative impedance boundary condition（IBC）are not efficient.A modified surface dual integral equation（M-SDIE）for targets with negative IBC is presented.A pure imaginary number is used to balance the formulations.It is proved that the M-SDIE is accurate and efficient with three numerical examples.The first numerical example shows that the M-SDIE is accurate compared with Mie.The second example shows that the presented SIE is efficient.In the third example,a missile head is selected to present the computing power of the M-SDIE.All the examples show that the M-SDIE is an efficient algorithm for negative IBC.

关键词： electromagnetic scattering impedance boundary condition （IBC） method of moments（MoM） surface integral equation